Dv 06 Actuation

7/31/2019 Dv 06 Actuation

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Dia-Flo

Diaphragm Valves

DiaphragmValve Actuation

Contained in this section:

Sizing Charts Other Available

Actuator Options

Pneumatic Actuation Types Features

DV-06 Section 3


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Dia-Flo Pneumatic Actuators

Dia-Flo

Diaphragm ValvesDiaphragm Valve Actuation

www.engvalves.com3 01 0 11/06

Features Include:

Compact Close-coupled actuators combine minimum space

with maximum economy.

Rugged Aluminum or ductile iron motor cases provide

maximum strength.

Low maintenance Only diaphragm and O-ring seals need

occasional replacement.

Efficient Seven interchangeable actuator sizes allow

maximum efficiency of available power.

Minimum number of parts Enclosed and protected from

atmospheric conditions.

Adaptability Suitable for pneumatic or hydraulic operation in

various pressure ranges.

Flexibility Can be mounted on any manual valve body already

in service.

Accessories Wide variety available, including: handwheel

closing device, positioner, adjustable travel stop, position

indicator, adjustable opening stop, limit switches and proximity

switches.

Actuator diaphragm Molded, nylon reinforced oil resistant

elastomer. Designed for long life at air pressures up to 85 psi.

Introduction

Dia-Flo pneumatic actuators are rugged, durable and long lasting.

Properly maintained, a service life of 20 plus years is not

uncommon. The actuator wear parts are limited to the nylon

reinforced diaphragm and Buna N O rings that require

infrequent replacement.

Modes of operation

On/Off control operation

Automatic throttling


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Actuator Series

3100 Series Fail Open Spring-to-Open, Air-to-Close

Dia-Flo



The actuator is spring-to-open, air-to-close

type. Operation is via a normally closed

3 way, 2 position (3/2) solenoid valve. When

the solenoid is energized, valve closes and

when de-energized, the valve opens. The

valve will fail open in the event of loss of

electrical power to the solenoid valve.

Piping Schematic for3/2 Solenoid ValveNormally Open

Air pressure on the top side of the actuator diaphragm closes the valve; a spring opensthe valve. Springs are available to open valve against full vacuum in the line. (Be sure tospecify when vacuum is involved.) The Dia-Flo air to close, spring to openactuator is available in sizes #12, #25, #50, #101, #130, #250.

ActuatorClose

A

DV

A

#12 #25 #50 #101 #130 #250


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Actuator Series

Dia-Flo



3200 Series Fail Close Spring-to-Close, Air-to-OpenThis is the reverse of the 3100 Series. The

valve is spring-to-close and air-to-open.

Operation is via a normally closed 3 way,

2 position (3/2) solenoid valve. When the

solenoid is energized, the valve opens and

when de-energized, the valve closes. The

valve will fail close in the event of loss of

electrical power to the solenoid valve.

Piping Schematic for3/2 Solenoid ValveNormally Closed

A

Actuator

Close

DV

A

#12 #25 #50 #75 #101 #130 #250

Air pressure on the underside of the actuator diaphragm opens the valve. A spring orset of springs closes the valve. This Dia-Flo air to open - spring to close actuator isavailalbe in sizes #12, #25, #50, #75, #101, #130 and #250.


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Actuator Series

Dia-Flo



3300 Series Double Acting Air to close, air to open

This type of actuator is similar in functional-

ity as a double acting piston cylinder.

Operation is via a 4 way, 2 position (4/2)

solenoid valve. Standard set-up is valve

closed when solenoid valve is de-energizes

and opens when energized. There is no fail

position unless provided with an auxiliary

source of air supply. Note that diaphragm

valves will tend to open when line pressure

is present.

Piping Schematic for4/2 Solenoid Valve

Double-acting (air to close, air to open) Dia-Flo actuators are available in seven diaphragm sizes:#12, #25, #50, #75, #101, #130, #250.

A Bctuator

Close

DV

A

B


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Actuator Series

Dia-Flo



3300 Series Double Acting Air to close, air to open

Alternatively, the valve can be controlled by means of two 3 way, 2 position (3/2) solenoid valves in lieu of one 4 way, 2 position (4/2)

solenoid valve. In this arrangement, one solenoid valve is allowing air to one side of actuator chamber and the other solenoid valve is

venting trapped air from the other chamber via the exhaust port.

In this schematic, snap acting relay is added to the control circuit and utilizing the normal air supply for pilot pressure source. This

arrangement can be used to lock the actuator in its last position in the event of loss of pilot pressure but the auxiliary air source port will

be plugged.

Note: We recommend use of dedicated air filter-regulator for each valve assembly because of different supply air pressure requirements.

This will extend valve diaphragm service life and keep speed of operation of valve unaffected by the fluctuating of supply air pressure.

Piping Schematic for Two (2) 3/2 solenoid Valves

Piping Schematic for 4/2 Solenoid Valve with Auxiliary Air Pressure

Air

Normally Closed

Normally Open

A

AA

B

B

B

Air

ExhaustSupply

B1

B

A1

A

C

Snap ActingRelay

A B

A

Double Acting

Actuator

Close

DV

B

C

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